| Message ID | 20180328190540.370956-1-ast@kernel.org |
|---|---|
| Headers | show |
| Series | bpf, tracing: introduce bpf raw tracepoints | expand |
On 03/28/2018 09:05 PM, Alexei Starovoitov wrote: > v7->v8: > - moved 'u32 num_args' from 'struct tracepoint' into 'struct bpf_raw_event_map' > that increases memory overhead, but can be optimized/compressed later. > Now it's zero changes in tracepoint.[ch] [...] > The first approach simply added these pointers to sched tracepoints: > https://lkml.org/lkml/2017/12/14/753 > which Peter nacked. > Few options were discussed and eventually the discussion converged on > doing bpf specific tracepoint_probe_register() probe functions. > Details here: > https://lkml.org/lkml/2017/12/20/929 > > Patch 1 is kernel wide cleanup of pass-struct-by-value into > pass-struct-by-reference into tracepoints. > > Patches 2 and 3 are minor cleanups to address allyesconfig build > > Patch 4 refactor trace_iwlwifi_dev_ucode_error from 17 to 4 args > > Patch 5 introduces COUNT_ARGS macro > > Patch 6 introduces BPF_RAW_TRACEPOINT api. > the auto-cleanup and multiple concurrent users are must have > features of tracing api. For bpf raw tracepoints it looks like: > // load bpf prog with BPF_PROG_TYPE_RAW_TRACEPOINT type > prog_fd = bpf_prog_load(...); > > // receive anon_inode fd for given bpf_raw_tracepoint > // and attach bpf program to it > raw_tp_fd = bpf_raw_tracepoint_open("xdp_exception", prog_fd); > > Ctrl-C of tracing daemon or cmdline tool will automatically > detach bpf program, unload it and unregister tracepoint probe. > More details in patch 6. > > Patch 7 - trivial support in libbpf > Patches 8, 9 - user space tests > > samples/bpf/test_overhead performance on 1 cpu: > > tracepoint base kprobe+bpf tracepoint+bpf raw_tracepoint+bpf > task_rename 1.1M 769K 947K 1.0M > urandom_read 789K 697K 750K 755K Applied to bpf-next, thanks everyone!
v7->v8: - moved 'u32 num_args' from 'struct tracepoint' into 'struct bpf_raw_event_map' that increases memory overhead, but can be optimized/compressed later. Now it's zero changes in tracepoint.[ch] v6->v7: - adopted Steven's bpf_raw_tp_map section approach to find tracepoint and corresponding bpf probe function instead of kallsyms approach. dropped kernel_tracepoint_find_by_name() patch v5->v6: - avoid changing semantics of for_each_kernel_tracepoint() function, instead introduce kernel_tracepoint_find_by_name() helper v4->v5: - adopted Daniel's fancy REPEAT macro in bpf_trace.c in patch 6 v3->v4: - adopted Linus's CAST_TO_U64 macro to cast any integer, pointer, or small struct to u64. That nicely reduced the size of patch 1 v2->v3: - with Linus's suggestion introduced generic COUNT_ARGS and CONCATENATE macros (or rather moved them from apparmor) that cleaned up patch 6 - added patch 4 to refactor trace_iwlwifi_dev_ucode_error() from 17 args to 4 Now any tracepoint with >12 args will have build error v1->v2: - simplified api by combing bpf_raw_tp_open(name) + bpf_attach(prog_fd) into bpf_raw_tp_open(name, prog_fd) as suggested by Daniel. That simplifies bpf_detach as well which is now simple close() of fd. - fixed memory leak in error path which was spotted by Daniel. - fixed bpf_get_stackid(), bpf_perf_event_output() called from raw tracepoints - added more tests - fixed allyesconfig build caught by buildbot v1: This patch set is a different way to address the pressing need to access task_struct pointers in sched tracepoints from bpf programs. The first approach simply added these pointers to sched tracepoints: https://lkml.org/lkml/2017/12/14/753 which Peter nacked. Few options were discussed and eventually the discussion converged on doing bpf specific tracepoint_probe_register() probe functions. Details here: https://lkml.org/lkml/2017/12/20/929 Patch 1 is kernel wide cleanup of pass-struct-by-value into pass-struct-by-reference into tracepoints. Patches 2 and 3 are minor cleanups to address allyesconfig build Patch 4 refactor trace_iwlwifi_dev_ucode_error from 17 to 4 args Patch 5 introduces COUNT_ARGS macro Patch 6 introduces BPF_RAW_TRACEPOINT api. the auto-cleanup and multiple concurrent users are must have features of tracing api. For bpf raw tracepoints it looks like: // load bpf prog with BPF_PROG_TYPE_RAW_TRACEPOINT type prog_fd = bpf_prog_load(...); // receive anon_inode fd for given bpf_raw_tracepoint // and attach bpf program to it raw_tp_fd = bpf_raw_tracepoint_open("xdp_exception", prog_fd); Ctrl-C of tracing daemon or cmdline tool will automatically detach bpf program, unload it and unregister tracepoint probe. More details in patch 6. Patch 7 - trivial support in libbpf Patches 8, 9 - user space tests samples/bpf/test_overhead performance on 1 cpu: tracepoint base kprobe+bpf tracepoint+bpf raw_tracepoint+bpf task_rename 1.1M 769K 947K 1.0M urandom_read 789K 697K 750K 755K Alexei Starovoitov (9): treewide: remove large struct-pass-by-value from tracepoint arguments net/mediatek: disambiguate mt76 vs mt7601u trace events net/mac802154: disambiguate mac80215 vs mac802154 trace events net/wireless/iwlwifi: fix iwlwifi_dev_ucode_error tracepoint macro: introduce COUNT_ARGS() macro bpf: introduce BPF_RAW_TRACEPOINT libbpf: add bpf_raw_tracepoint_open helper samples/bpf: raw tracepoint test selftests/bpf: test for bpf_get_stackid() from raw tracepoints drivers/infiniband/hw/hfi1/file_ops.c | 2 +- drivers/infiniband/hw/hfi1/trace_ctxts.h | 12 +- drivers/net/wireless/intel/iwlwifi/dvm/main.c | 7 +- .../wireless/intel/iwlwifi/iwl-devtrace-iwlwifi.h | 39 ++--- drivers/net/wireless/intel/iwlwifi/iwl-devtrace.c | 1 + drivers/net/wireless/intel/iwlwifi/mvm/utils.c | 7 +- drivers/net/wireless/mediatek/mt7601u/trace.h | 6 +- include/asm-generic/vmlinux.lds.h | 10 ++ include/linux/bpf_types.h | 1 + include/linux/kernel.h | 7 + include/linux/trace_events.h | 42 +++++ include/linux/tracepoint-defs.h | 6 + include/trace/bpf_probe.h | 92 +++++++++++ include/trace/define_trace.h | 1 + include/trace/events/f2fs.h | 2 +- include/uapi/linux/bpf.h | 11 ++ kernel/bpf/syscall.c | 78 +++++++++ kernel/trace/bpf_trace.c | 183 +++++++++++++++++++++ net/mac802154/trace.h | 8 +- net/wireless/trace.h | 2 +- samples/bpf/Makefile | 1 + samples/bpf/bpf_load.c | 14 ++ samples/bpf/test_overhead_raw_tp_kern.c | 17 ++ samples/bpf/test_overhead_user.c | 12 ++ security/apparmor/include/path.h | 7 +- sound/firewire/amdtp-stream-trace.h | 2 +- tools/include/uapi/linux/bpf.h | 11 ++ tools/lib/bpf/bpf.c | 11 ++ tools/lib/bpf/bpf.h | 1 + tools/testing/selftests/bpf/test_progs.c | 91 +++++++--- 30 files changed, 607 insertions(+), 77 deletions(-) create mode 100644 include/trace/bpf_probe.h create mode 100644 samples/bpf/test_overhead_raw_tp_kern.c